1. Field of the Invention
The invention relates to a heat and flame resistant fabric for use as single or outer layer of protective garments.
2. Description of Related Art
A garment protecting against heat and flame is also known as “Turn Out Coat” and is usually used as uniform to identify, for example, a fire fighter. Such garment is normally quite heavy because the mass and the thickness of the garment itself are normally the main factors conferring protection. The wearer of such a garment is therefore limited in his movements and undergoes heat stress so that the overall wear comfort strongly decreases. In the last twenty years, attempts have continuously been made to develop new materials in order to improve the wear comfort of such protective garments. For example, lighter but more voluminous insulating materials have been developed for this purpose. These materials confer more lightness to the final protective garment but they might affect the respiratory activities of the wearer due to their cumbersome dimensions. Furthermore, the freedom of movement is not necessarily improved by using these materials.
Garments protecting against heat and flame are usually made of one or more layers. The choice of the different materials and of the number of layers constituting the final protective garment depends on the specific application of the garment itself.
When designing a new protective garment, care must be taken that all criteria of the relevant national and international norms are fulfilled. As an example, heat and flame resistant garments must be manufactured in accordance with EN-340, EN-531, EN 469 as well as NFPA 1971:2000, NFPA 2112:2001, and NFPA 70E:2000. For instance, a lighter protective garment could be manufactured by simply using lighter materials. However, this is usually associated with a decrease of the mechanical and thermal properties of the protective garment.
Furthermore, the Turn Out Coats are normally used by most of the fire brigades for an average period of five years and, therefore, it is expected that they fully maintain their performance in terms of heat and flame resistance, as well as in terms of their esthetic appearance, during such period of time.
WO 00/066823 discloses a fire resistant textile material comprising a woven faced fabric which may include poly-m-phenylenisophtalamid (meta-aramid) fibers, the fabric including a woven mesh back of low thermal shrinkage fibers.
WO 02/079555 discloses a reinforced fabric comprising a ground fabric having on its rear surface a reinforced grid consisting of warp and weft yarns produced in a material having higher mechanical properties than those producing the yarns of the ground fabric. In such reinforced fabric, the reinforcing grid is linked to the ground fabric by its warp and weft yarns which are fixed on the ground fabric in different points and which intersect each other outside the ground fabric.
The products developed under the two prior art documents mentioned above increase the mechanical and thermal performance of single ply structures. However, by adding such a reinforcing grid at the backside of the single ply layer, the fabrics according to these prior art documents become a semi double weave structure so that their specific weights are necessarily higher than those of strict single ply fabrics.
The problem at the root of the present invention is therefore to provide a heat and flame resistant single ply fabric which maintains its performance and esthetic appearance over the years and which, if used as single or outer layer of protective garments, enables to increase wear comfort and to improve the dissipation of vapor and heat produced by the wearer.